feat(19334): Improve the design for policy checks

[vanch3d]

See https://hivemq.kanbanize.com/ctrl_board/57/cards/19334/details/

The PR changes the unsatisfactory UX flow for the policy checks and reporting, as implemented in https://github.com/hivemq/hivemq-edge/pull/288

The PR also removes the checkered background (keep the canvas plain) and fixes a few of the translations (see 19310)

Design

• The canvas toolbox (top-left corner) is redesigned as accordion-like multiple containers for policy operations: build, check and publish
• The drag-and-drop components have been relocated in the first panel
• The verify your construction panel is available by clicking on the icon or by using the navigation arrows as soon as at least two connected nodes are added to the canvas
• The 'checkbutton is enabled when adata policyorbehaviour policy` is selected on the canvas
• The check runs exactly as before, marking the walked nodes on the canvas
• Errors are indicated by an alert message, as well as a list of errors, as before
• The publish panel and button become enabled as soon as the report runs successfully (success alert, no error listed)
• The check and report are persisted in a local store: navigating away and back still shows the running checks (if unfinished) and the report.
• To run another check, the report needs to be closed.

Out-of-scope

• The publish button is disabled and will be handled in the next ticket, see 19497

Before

After